Simple Approach for Building High Transconductance Paper-Based Organic Electrochemical Transistor (OECT) for Chemical Sensing

Adil Ait Yazza, Pascal Blondeau, Francisco J. Andrade
ACS Applied Electronic Materials
doi: 10.1021/acsaelm.1c00116

Organic electrochemical transistors (OECTs) have attracted great interest in the last few years as biochemical sensors due to their outstanding analytical performance, versatility, stability, and easiness of fabrication. While thin-film OECTs have been studied extensively, their manufacturing still presents some challenges. This report presents a simple approach for developing OECT using a paper substrate and a thick-film approach that shows outstanding performance. The channel is hand-made by dip pen deposition of the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS). This allows reproducible channel thickness in the order of 6 μm, well above the conventionally used values. This device displays a high transconductance that exceeds 40 mS and an on-to-off current ratio of 3.8 × 10³ comparable or superior to the state-of-the-art paper-based OECTs. The advantages of this approach are illustrated with the detection of H2O2 and glucose, obtaining sensitivities above 1.5 mA/dec. This simplified approach and high sensitivity may help to extend the use of the OECT-based sensors, particularly in the distributed and point-of need applications.

Modulating the mixed potential for developing biosensors: Direct potentiometric determination of glucose in whole, undiluted blood

Cánovas, R., Blondeau, P., Andrade, F.J.
Biosensors and Bioelectronics 2020, 163 article number 112302. Doi: 10.1016/j.bios.2020.112302

This work presents a novel strategy to control the mixed potential that allows the development of a potentiometric biosensor for the direct detection of glucose in whole, undiluted blood without any sample pretreatment. The accurate measurement of blood sugar levels in a single drop of whole blood with excellent recovery is presented.

Paper-based Potentiometric Biosensor for Monitoring Galactose in Whole Blood

Mohamed Bouri, Julio C. Zuaznabar-Gardona, Marta Novell, Pascal Blondeau, Francisco J. Andrade
Electroanalysis 2020, doi: 10.1002/elan.202060285

A filter paper sputtered with a layer of Pt and subsequently coated with a Nafion® membrane is used as working electrode. The mixed potential of the Pt electrode allows the detection of H2O2 generated by the oxidation of galactose in the presence of the galactose oxidase enzyme. This provides a simple and mediator‐free approach method. The system shows sensitivity values of −62.8±9.4 mV/decade of galactose in the range from 0.3 to 31.6 mM, well within the clinical relevant range. MnO2 nanoparticles were added to decrease the interference from ascorbic acid so that validation of the sensor in whole blood samples was performed with good recovery.

Controlling the mixed potential of polyelectrolyte-coated platinum electrodes for the potentiometric detection of hydrogen peroxide

Jhonattan F. Baez, Matthew Compton, Sylviane Chahrati, Rocío Cánovas, Pascal Blondeau, Francisco J. Andrade
Analytica Chimica Acta 2020, 1097(8) 204-213, doi: 10.1016/j.aca.2019.11.018

The use of a Pt electrode coated with a layer of Nafion has been described in previous works as an attractive way to perform the potentiometric detection of hydrogen peroxide. Despite the attractive features of this approach, the nature of the non-Nernstian response of this system was not properly addressed. This work provides a phenomenological view of the problem. A general framework to understand the factors that affect the potentiometric response is provided. Experimental evidence showing that the use of polyelectrolyte coatings are a powerful way to control the mixed potential open new ways for the development of robust and simple potentiometric sensors.

A novel point-of-care device for blood potassium detection of patients on dialysis: Comparison with a reference method

Marta Novell, Nayra Rico, Pascal Blondeau, Miquel Blasco, Adrià Maceira, José Luis Bedini, Francisco Javier Andrade, Francesc Maduell
Letter to the editor in Nefrología, doi: 10.1016/j.nefro.2019.06.002

Determination of potassium levels in serum is routinely performed in clinical labs, as it is a critical parameter and abnormal potassium concentrations may lead to fatal cardiac consequences. An immediate test for determination of blood potassium may contribute to prevent such critical issues, for example, arrhythmias. Therefore we have developed and tested a novel point-of-care (POC) device that provides a simple and highly affordable way of measuring potassium levels in a single drop of blood outside the clinical laboratory. This POC device has demonstrated a good correlation with the reference method, proving that it can be an alternative for specific situations where an immediate response is required.

Ionophore-Based Optical Sensor for Urine Creatinine Determination

Miguel M. Erenas, Inmaculada Ortiz-Gómez, Ignacio de Orbe-Payá, Daniel Hernández-Alonso, Pablo Ballester, Pascal Blondeau, Francisco J. Andrade, Alfonso Salinas-Castillo, and Luis Fermín Capitán-Vallvey
ACS Sensors 2019, 4, 421-426
doi: 10.1021/acssensors.8b01378

An optical disposable sensor for monitoring creatinine levels in urine is described in this paper. The new sensor displays a good response time to creatinine (approximately 3 min) over a wide dynamic range (from 1 × 10−5 to 1 × 10−2 M). Moreover, the optical selectivity coefficients obtained for creatinine over common cations present in urine meet the requirements for real sample measurements, providing a simple, quick, cost-effective, and selective alternative to the conventional methodology based on Jaffe’s reaction.

Knowledge valorization

The research group has obtained one of the URV’s knowledge valorization funds (URV R2B) with the project ‘Sensors, smartphones and cloud: A seamless platform for healthcare’